Known indoor units included in ceiling-concealed air-conditioning apparatuses each include a housing embedded in the ceiling and having a square sectional shape, a fan and an air inlet provided in a central part of the housing, and a heat exchanger surrounding the fan. Hence, room air that is taken in substantially upward by the fan is redirected in the fan in such a manner as to flow substantially horizontally toward the periphery. Subsequently, the air is redirected downward after flowing through the heat exchanger, and is blown from air outlets into the room.
In the above case, the airflow is guided and redirected by the inner surface of the housing. Because of the inertia of the airflow, the airflow is not completely redirected, but the speed of the airflow increases in an area near the inner surface of the housing (in an area far from the fan), making the distribution of airflow speed at the air outlets nonuniform.
Accordingly, uniform-airflow-speed means (means that makes the distribution of airflow speed at an air outlet uniform) is disclosed (see Patent Literature 1, for example), in which a deflection guide having a triangular prism shape is provided on the inner surface of the housing; an air-passage wall portion is provided by making a recess in a portion of a wall provided below a heat exchanger and that faces the deflection guide so that the sectional area of the air passage becomes substantially uniform; and an enlarged air passage portion is provided immediately after a downstream end of the deflection guide.